Controlling system.



H. M. BASCOM.

CONTROLLING SYSTEM.

APPLICATION FILED IuLY 22, I916.

Patented July 3, 1917. 7

To "all whom it may concern:

HENRY M. BASCOM, OF BROOKLYN, NEW YORK, ASSIGNOR TO AND TELEGRAPH COMPANY, A CORPORATION OF AMERICAN TELEPHONE NEW YORK.

CONTROLLING srsrnm.

Application filed uly 22, 1916. Serial N 0. 110,738.

Be it known that I, HENRY M. BASGOM, residing at Brooklyn, in the countyof Kings and State 'of New York, have invented certain Improvements in Controlling Systems, of which the following is a specification.

In telephonic, telegraphic or other signaling systems, the operation in the ordinary manner of certain indicating or signaling apparatus may introduce difliculties through complication of the circuits, presence of earth potentials or the lack of suflicient current margins. The present invention takes advantage of changes of resistance to disturb a potential balance normally maintained in a controlling apparatus, which leads to its functionating, and there is thereby obtained a sensitive and generally eflective controlling system.

The accompanyingdrawing illustrates a single embodiment of the invention, Figure 1 showing diagrammatically -my improved system applied to the control of a subscrib- L is shown uniting ers signal associated with a telephone service observing circuit, while Fig. 2 is a schema illustrating the principle of the invention.

Circuits for observing the character of service rendered telephone subscribers are ordinarily provided with a lamp signal at the observers desk, governed by a relay so connected that itrfollows in its energization and deenergization the opening and closing of the substation hookswitch contacts. It is possible to join this relay in series with the substation line or to connect. it to groundin parallel with one winding of the repeating coil in the A operators cord circuit. In the first instance, the opening of the subscribers line and the introduction of a connection may cause trouble, while in the second, the evil eii'ect of earth potentials may be encountered and machine ringing is interfered with. i In this particular application of my invention, I control the subscribers signal through the change of resistance in the sleeve conductor of the connected cord circuit, due to the placing of a shunt upon a supervisory lamp when the subscriber takes down the receiver. This affects a Wheatstone-balance including in its bridge a signal controlling relay.

Referring to Fig. 1 of the drawing, the line the usual substation set A with the answering jack J at a central sta- Speoification of Letters I'atent.

Patented July 3, 1917.

tion To the sleeve conductorof the line is ]01I1ed 1ts cut-ofi relay R. Cooperating with the jack J is the plug P of a cord or connecting circuit, the answering end of which 7 .40 ohm shunt r through the front contact of relay R.

To the substation line L is connected the service observing line L. The observers head telephone T is associated with the talking conductors, and at the position of said observer is a subscribers signal lamp 0, the other equipment of the position not appearing. The lamp 0 is in a. local circult controlled in the contacts of a sensitive relay R conveniently furnished by substituting for the needle of a voltmeter having an oscillating coil 10, a contact arm 11. This arm is normally held against a stop 13 by a light spring 14 and moves into the contact with a stop 15 when current passes through the coil 10 in the proper di-.

rection. One terminal of the coil of this relay is connected to the third, or sleeve, conductor of the observed line through a conductor 12 of the service observing line, while the other terminal is joined to the opposite poles of the battery through reslstances r and 1' of 5000 and 29,750 ohms, respectively. From Fig. 2 it will be clear that thecircuit of Fig. 1 forms a Wheatstone-balance circuit, in which-the side (1 contains the windings of the cut-01f relay R, the resistance of which is 30 ohms, the side I), the resistance r normally in series with the lamp 0, but with this shunted by the resistance 1" when relay R is energized,

mined resistances r and r and the bridge conductor 6, the winding of relay R With the receiver at substation A upon its hook, and therefore with the relay R deenergized, the values of the resistances are such that there is at least an approximate balance of potentials at the terminals of the relay R and the arm 11 is held against the normal stop by its spring. On account of the variation in commercial resistance coils, it is impracticable to provide for an accurate balance under all conditions. Therefore the resistances r and r are preferably so chose'n that the potentials at the terminals of relay R are substantially equal for.

the winding 10 of relav R the arm. ll 'to swing into contact with stop 15, closing the local circuit of the lamp 0' turn the arm llofrelay R phone line,

V I and a service observing at the observing position, so that said lamp 'phone line,

is illuminated to indicate to the observer the act of the subscriber. Upon the return of the receiver to its hook the normal condition of potential at the bridge terminals is restored, permitting the spring 14 to reto its stop 13, opening the local circuit to extinguish the lamp 0.

While the invention is here discussed in cpnnection with a particular portion of one type of signaling system, it is to be understood that its field is by no means thus limited, but may cover many instances in which it is desired that changes in resistance shall produce circuit controlling operations.

'I claim as my invention:

,1. In a service observing system, a telea connecting circuit therefor, a signal associated with the circuit and controlled by conditions in the line, a relay signal controlled thereby, and means for maintaininga balance of potential at the terminals of ,the relay, erate the relay and display the service observing signal upon a changed condition ,of the first-named signal.

2. In a service observing system, a tele-.

phone line, a connecting circuit therefor provided with asupervisory signal, a service observing line, a signal circuit controlling relay having its winding in said line, means including maintaining a balance of potential at two points on opposite sides of said relay winding, and a supervisory relay in the connecting circuit for controlling said supervisory signal and through the signal the balance of said potentials to operate said circuit controlling relay.

3. In a service observing system, a telephone line, a connecting circuit therefor provided with a supervisory signal, a service observing line including a circuit controlling relay, means including said signal for normally maintaining two points on opposite sides of said relay at the same pcthe si a1 0. Theresistance ofv flow through said balance being disturbed to opthe supervisory signal for tential, and a supervisory relay in the connecting circuit. adapted on energization to .withdrawsaid signal and unbalance said potentials to operatethe circuit-controlling relay.

4. In a service observing system, a telephone line, a connecting circuit therefor provided witha supervisory signal, a shunt for and a supervisory relay governing said unt, a Wheatstone-balance'one side of which includes said signal and shunt, circult-controlling means in the bridge of the balance, and a service observing'signal circuit controlled thereby,- said means becoming operative on change of resistance in the balance by operation of the supervisory relay. 7

5. In a service observing system, a telea connecting circuit therefor, a supervisory signal associated with the circuit and provided with a shunt circuit, a Wheatstone-balance two sides of which include a cut-off relay and said signal and shunt, the companionsides including predetermined resistances, circuit controlling means in the bridge of,the balance, and a service observing signal under control of said means and being effective on closing the shunt by operation of the supervisory relay.

6. In a telephone system, a telephone line, a connecting circuit therefor, a Wheatstonebalance, comprising; in two sides, a cut-off relay and a supervisory signal included in the connecting circuit, and in the companion sides, predetermined resistances; circuit-controlling apparatus in the bridge of the balance, a service observing signal circuit controlled thereby, and a supervisory relay responsivc to the conditions in the line adapted to alter the side resistance containing the first-named signal and thereby operate the service observing signal.

7. In aservice observing system, a telephone line, a connecting circuit. therefor provided with .a supervisory signal in its sleeve conductor, a service observing line having a conductor joined to the sleeve conductor of the telephone line and connecting circuit, a relay with its winding included in said service observing conductor, and means for maintaining a balance of potential at the terminals of the relay during the display of the supervisory signal, said balance being disturbed upon the withdrawal of the signal to cause the operation of the relay.

8. In a service observing system, a telephone line and its cut-ofi relay, a connecting circuit therefor provided with a supervisory signal in its sleeve conductor, a shunt for the si a1 and asupervisory relay governing said s unt, a service observing line having a conductor joined to the sleeve conductor of the telephone line and connecting circuit, a

stone-balance having the service observing line conductor and the winding of the sensitive relay furnishing the bridge conductor, one of the sides of the balance including the supervisory signal and its shunt,,the side of the balance upon the-op osite side of the bridge in'cluding'the winding of the cut-ofl' relay and the other two sides being of predetermined-resistance, and an observers signal controlled by the sensitive relay,

9. In a telephone system, line sleeve and connecting circuit sleeve contacts, line con-' nections associated therewith including a cut-off relay and a variable resistance, a Wheatstone-balance one branch of which includes said relay and variable resistance, and circuit controlling ap aratus in the bridge of the balance adapte to operate when said resistance is altered.

10. In a telephone system, line" sleeve and connecting circuit sleeve contacts, line connections-associated therewith, the resistance of one of said connections being adapted to be altered in the operation of the system, a

Wheatstone-balance one side of which includes said variable resistance, and circuit controlling apparatus in the bridge of the balance adapted to operate when said resistance is altered. 1

11. The combination with a telephoneline and its cut-01f, relay, of a variable resistance, a Wheatstone-balance one side of which includes the relay and variable resistance, and a-circuit-controlling apparatus included in the bridge of the balance and being adapted to operate upon a variation in said resist- 12. In a telephone system, the combination with a central station and a telephone line extendingnto the central station and being provided with a local circuit thereat, of a variable resistance connected with said local circuit, a Wheatstone-balance one side of which includes the variable resistance, and a circuit controlling apparatus included in the bridge of the balance and being adapted to operate upon a variation in said resist:

ance; p

13. In a telephone system, the combination with a central station and a telephone line extending to the central station and being provided with a local conductor thereat,

' of a connecting circuit having a local con- Au'nnn KAUFMANN, CLIFFORD C. 

